Recent consumer interest in personal health has led to a variety of personal health monitoring devices being offered on the market. Such devices, until recently, tended to be complicated to use and were typically designed for use with one activity, e.g., bicycle trip computers.
Recent advances in sensor, electronics, and power source miniaturization have allowed the size of personal health monitoring devices, also referred to herein as “biometric tracking” or “biometric monitoring” devices, to be offered in extremely small sizes that were previously impractical. For example, the Fitbit Ultra is a biometric monitoring device that is approximately 2″ long, 0.75″ wide, and 0.5″ deep; it has a pixelated display, battery, sensors, wireless communications capability, power source, and interface button, as well as an integrated clip for attaching the device to a pocket or other portion of clothing, packaged within this small volume.
The disclosure provides methods and devices for activating, in energy efficient ways, HR monitor based on user motion and skin proximity. The disclosure also provides methods for operating the LED and photo detector of heart rate monitors to obtain accurate reading of heart rate tailored for different user characteristics such as skin colors.